Manko V. Transmembrane calcium transporting systems in secretory cells of Chironomus plumosus Linnaeus salivary glands

It have been established in secretory cells of researched fewcellular glands next Ca2+-transporting systems are available: voltage-operated Ca2+ channels, Na+-Ca2+ exchanger, plasma membrane and endoplasmic reticulum Ca2+ pump, mitochondrial Ca2+ uniporter, IP3R and RyR, P2Y- and P2X-receptors. Na+-Ca2+ exchanger have been characterized with low specific to mono- and divalent cations and it is an evidence of catalytic regulation with cytosolic Ca2+. Intracellular medium alkalization cause current amplitude of Na+-Ca2+ exchange decreasing as a result of, possibly, that catalytic regulation breaking. Transition d-elements cations (Cd2+, Ni2+, La3+) have different influence over Na+-Ca2+ exchange through the plasma membrane, which defined with their ability to form complexes with different ligands. On the basis of experimental data Ca2+-functional unit conception and Ca2+-domain organization conception of secretory cells have been proposed. Calmoduline stimulates, simultaneously, both active and passive Ca2+-transporting systems according to proposed "shifted phases" principle. Cyclic AMP, cGMP and NO are effective intracellular Ca2+-transporting systems regulators also. On the basis of dimensional properties analysis of secretory cells and different Ca2+-transporting systems properties have been provided for availability of three distinctly limited calcium domains (basal, apical and nuclear), formed with active part of plasma and intracellular membranes, have different set of Ca2+-transporting systems and have different functions.